1. Field of the Invention
This invention relates to a preloader apparatus, and in particular relates to a preloader apparatus for tensing a seat belt of a vehicle when acceleration is applied to the vehicle.
2. Description of the Related Art
A conventional preloader apparatus is disclosed in the Japanese Utility Model Laid Open No. 3 (1991)-51657. The preloader apparatus disclosed in the prior art comprises a base member fixed to a vehicle, an operating member operated by acceleration applied to the vehicle, a rod movably mounted on the base member, a first link pivotably mounted on the base member and connected with the operating member, a second link connected with the first link and the rod so as to move the rod by rotation thereof. In accordance with the prior art, when the first link is rotated by the operation of the operating member, the second link is disconnected with the rod so as to let the rod be moved by an elastic force of a spring. Therefore, an anchor of the seat belt is moved in a direction to tense the seat belt.
Another conventional preloader apparatus is disclosed in the Japanese Patent Laid Open No. 2 (1990)-256550. This preloader apparatus disclosed in the prior art comprises a base member fixed to the vehicle, an operating member operated by acceleration applied to the vehicle, a rod movably mounted on the base member, a first link bendably mounted on the base member and connected with the operating member, a second link connected with the first link and the rod so as to move the rod by rotation thereof. In accordance with the prior art, when the first link is bent by the operation of the operating member, the second link is disconnected with the first link so as to release the rod so it can be moved by an elastic force of a spring disposed between the rod and the base member. Therefore, an anchor of the seat belt is moved in a direction to apply tension to the seat belt.
However in accordance with the prior arts, since the operation of the first link is not regulated, the second link that prevents the rod from moving can be set free toward the operational direction. Therefore, when an acceleration under a predetermined value to be detected is applied to the vehicle, the operation of the preloader apparatus becomes unstable.